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US 6,199,381 B1Granted
DC centering of free piston machine
AssigneeSunPower Corporation
InventorsReuven Z-M Unger, Douglas E. Keiter
Life of this patent
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AssigneeSunPower Corporation
InventorsReuven Z-M Unger, Douglas E. Keiter
Estimating the term…
In a free piston machine, a coil is mounted to its housing and magnetically linked to a permanent magnet or electromagnet on its piston member to form a linear motor. The coil and magnet are either added to embody the invention or are part of an AC linear alternator or AC linear motor which are a part of the free piston machine. A source of DC electrical current and a switch for connecting the DC source to the coil supply DC current to the coil when the switch is closed so that the coil and magnet temporarily operate as a DC linear motor until the piston is adequately centered for start-up without collision. The DC source voltage is temporarily applied to the coil to move the piston away from an end wall of the cylinder. This is accomplished by applying the DC current to the coil for a predetermined time interval, or by sensing when the piston has reached an adequately centered position.
A piston centering apparatus for moving a free piston member, which includes a piston slidably reciprocatable in a cylinder formed in a housing member, away from an end wall, the piston separating two fluid spaces bounding its opposite ends, the apparatus comprising:
In a free piston apparatus having a piston slidably reciprocatable in a cylinder formed in a housing member and a magnet mechanically linked to one of said members and magnetically linked to a coil mounted to the other said member to form an AC electromechanical linear transducer, the piston separating two fluid spaces bounding its opposite ends, a piston centering apparatus for moving the piston away from an end wall of the cylinder, the apparatus comprising:
A method for initiating the start up of a free piston apparatus having a piston slidably reciprocatable in a cylinder formed in a housing member and a magnet mechanically linked to one of said members and magnetically linked to a coil mounted to the other said member, the method comprising:
Dependencies are inferred from the claim text.